Dr David Humphreys

The estimated lifetime prevalence of physical or sexual intimate partner violence (IPV) is 30% among women worldwide. Understanding risk and protective factors is essential for designing effective prevention strategies.To quantify the associations between prospective-longitudinal risk and protective factors and IPV and identify evidence gaps.We conducted systematic searches in 16 databases including MEDLINE and PsycINFO from inception to June 2016. The study protocol is registered with PROSPERO (CRD42016039213).We included published and unpublished studies available in English that prospectively analyzed any risk or protective factor(s) for self-reported IPV victimization among women and controlled for at least 1 other variable.Three reviewers were involved in study screening. One reviewer extracted estimates of association and study characteristics from each study and 2 reviewers independently checked a random subset of extractions. We assessed study quality with the Cambridge Quality Checklists. When studies investigated the same risk or protective factor using similar measures, we computed pooled odds ratios (ORs) by using random-effects meta-analyses. We summarized heterogeneity with I2 and τ2. We synthesized all estimates of association, including those not meta-analyzed, by using harvest plots to illustrate evidence gaps and trends toward negative or positive associations.Of 18 608 studies identified, 60 were included and 35 meta-analyzed. Most studies were based in the United States. The strongest evidence for modifiable risk factors for IPV against women were unplanned pregnancy (OR = 1.66; 95% confidence interval [CI] = 1.20, 1.31) and having parents with less than a high-school education (OR = 1.55; 95% CI = 1.10, 2.17). Being older (OR = 0.96; 95% CI = 0.93, 0.98) or married (OR = 0.93; 95% CI = 0.87, 0.99) were protective.To our knowledge, this is the first systematic, meta-analytic review of all risk and protective factors for IPV against women without location, time, or publication restrictions. Unplanned pregnancy and having parents with less than a high-school education, which may indicate lower socioeconomic status, were shown to be risk factors, and being older or married were protective. However, no prospective-longitudinal study investigated the associations between IPV against women and any community or structural factor outside the United States, and more studies investigated risk factors related to women as opposed to their partners. Public health implications. This review highlights that prospective evidence for perpetrator- and context-related risk and protective factors for women's experiences of IPV outside of the United States is lacking and urgently needed to inform global policy recommendations. The current evidence base of prospective studies suggests that, at least in the United States, education and sexual health interventions may be effective targets for preventing IPV against women, with young, unmarried women at greatest risk.

Features of the urban neighbourhood influence the physical, social and mental wellbeing of residents and communities. We explored the longitudinal association between change to the neighbourhood built environment and the wellbeing of local residents in deprived areas of Glasgow, Scotland.A cohort of residents (n = 365; mean age 50 years; 44% male; 4.1% of the 9000 mailed surveys at baseline) responded to a postal survey in 2005 and 2013. Wellbeing was assessed with the mental (MCS-8) and physical (PCS-8) components of the SF-8 scale. We developed software to aid identification of visible changes in satellite imagery occurring over time. We then used a Geographical Information System to calculate the percentage change in the built environment occurring within an 800 m buffer of each participant's home.The median change in the neighbourhood built environment was 3% (interquartile range 6%). In the whole sample, physical wellbeing declined by 1.5 units on average, and mental wellbeing increased by 0.9 units, over time. In multivariable linear regression analyses, participants living in neighbourhoods with a greater amount of change in the built environment (unit change = 1%) experienced significantly reduced physical (PCS-8: -0.13, 95% CI -0.26 to 0.00) and mental (MCS-8: -0.16, 95% CI -0.31 to - 0.02) wellbeing over time compared to those living in neighbourhoods with less change. For mental wellbeing, a significant interaction by baseline perception of financial strain indicated a larger reduction in those experiencing greater financial strain (MCS-8: -0.22, 95% CI -0.39 to - 0.06). However, this relationship was reversed in those experiencing lower financial strain, whereby living in neighbourhoods with a greater amount of change was associated with significantly improved mental wellbeing over time (MCS-8: 0.38, 95% CI 0.04 to 0.72).Overall, we found some evidence that living in neighbourhoods experiencing higher levels of physical change worsened wellbeing in local residents. However, we found a stronger negative relationship in those with lower financial security and a positive relationship in those with higher financial security. This is one of few studies exploring the longitudinal relationship between the environment and health.

We recently read the article by Benton et al. which reviewed risk of bias in natural experimental studies investigating the impact of the built environment on physical activity (Benton et al., 2016; Int J Behav Nutr Phys Act 13:107). As a technical exercise in assessing risk of bias to understand study quality, we found the results of this study both interesting and potentially useful. However, it prompted a number of concerns with the use of risk of bias tools for assessing the quality of evidence from studies exploiting natural experiments. As we discuss in this commentary, the rigid application of such tools could have adverse effects on the uptake and use of natural experiments in population health research and practice.